The invention relates to apparatus for reversing a rotatory direction of a motor, which is used for an auto-reverse type microcassette tape recorder.
A stable rotation is required for a motor used in a tape deck, because the stability of rotation greatly influences the wow and flutter characteristics of the tape deck. To this end, a motor for a one-motor type reversible tape deck is generally provided with two servo circuits, one for a forward rotation and the other for a reverse rotation. The reason for this is that the rotary characteristic of the motor has a transfer function expressed by a ratio of a mechanical output to an electric input of the motor, which depends on the rotary direction of the motor. In view of assembling such servo systems into a miniature mechanism such as a microcassette deck, the two-servo system encounters a difficulty that a restricted space rejects its use. The employment of the two-servo system increases the occurence of troubles in the servo circuits and the number of adjusting steps, resulting in an increase of cost to manufacture.
A motor with much the same characteristics for both the forward and the reverse rotations of the motor has recently been developed and put into a practical use. Such a motor has found its application in a so-called direct drive motor (DD) widely used in disc players or tape recorders currently being marketed. As far as the inventor knows, a miniature type device such as a microcassette tape recorder never employed a motor rotation direction reversing circuit capable of controlling the motor equally well in both the forward and reverse directions by a single servo system.